In the metallurgical industry there are different processes in which liquid metal is to be processed in one way or another. One example is the casting of metal, such as steel. In part of such a casting process, the liquid metal is supplied from a ladle via a pouring nozzle to a tundish. The metal flows from the tundish via a pouring nozzle to a casting mould or chill mould, in which the metal is cooled and transformed into solid form.
The supply and the flow of the metal through the pouring nozzle is very important in order to produce a configuration of flow in the chill mould that gives optimal conditions as regards the solidification of the metal and as regards the use of additives, such as casting powder or lubricant.
Moreover, it is important to prevent solid material, such as aluminium oxides, from accumulating on the inside of the pouring nozzle and in its outlet openings. Such solid material can, on the one hand, cause clogging of the pouring nozzle and the openings and, on the other, affect the flow and thus the casting process and the quality of the end product.
By way of today's technique, it is a problem to ensure that a metal flow which is located in the pouring nozzle is favorable for the casting process, since the metal is hidden or not visible as it flows through the pouring nozzle. Attempts are made to estimate what the flow looks like inside the pouring nozzle by, for instance, water modelling or mathematical modelling. However, these methods mostly take stationary conditions into account. In reality, marked variations can arise in the flow due to, for example, interference from a flow-controlling unit, such as a stopper or sliding gate, asymmetry in the flow, a varying level in the tundish and clogging of the nozzle.
Usually some form of gas, such as argon, is injected into the pouring nozzle in order to prevent clogging. However, this results in a secondary effect, implying that the flow then can change.